Several web-based tools allow you to convert PMD files to JPG for free without registration: Convert PMD to JPG for free - ImageToStl

Since most modern tools support PDF but not PMD, convert to PDF first: Use Online2PDF to turn the PMD into a PDF.

If you'd like, I can help you for batch converting large folders of PMD files or troubleshoot formatting issues in your converted JPGs. Which would you prefer?